Mechanical moving structure for an x-ray apparatus

ABSTRACT

A mechanical moving device for displacement of an X-ray tube and a carrier for X-rays sensitive material in opposite directions along adjustable paths about a support, arranged between the Xray tube and the carrier by means of a driving member which is rotatable, via a tripartite arm, about a stationary shaft, the individual parts thereof being arranged to the rotatable by means of connection shafts, the driving of the rotatable parts being controlled by the actuation or switching off of coupling members.

United States Patent [191 Rouge et al.

[ MECHANICAL MOVING STRUCTURE FOR AN X-RAY APPARATUS 21 Appl. No.: 272,732

[30] Foreign Application Priority Data July 29, 1971 France 7127804 [52] US. Cl. 74/86, 33/30 G [51] Int. Cl. F16h 35/16 [58] Field of Search 74/52, 86, 22 R, 665 P,

[56] References Cited UNITED STATES PATENTS 1,872,973 8/1932 Kittelmi 33/30 G 1 C B A [451 May 7,1974

Primary ExaminerA1lan D. Herrmann Attorney, Agent, or Firm-Frank R. Trifari [5 7] ABSTRACT A mechanical moving device for displacement of an X-ray tube and a carrier for X-rays sensitive material in opposite directions along adjustable paths about a support, arranged between the X-ray tube and the carrier by means of a driving member which is rotatable,

via a tripartite arr'n, about a stationary shaft, the individual parts thereof being arranged to the rotatable by means of connection shafts, the driving of the rotatable parts being controlled by the actuation or switching off of coupling members.

5 Claims, 3 Drawing Figures memenm 71914 8L808L888 sumlnfs MECHANICAL MOVING STRUCTURE FOR AN X-RAY APPARATUS BACKGROUND OF THE INVENTION The invention relatesto a mechanical moving structure for displacement of a driving member by means of which an X-ray tube and a carrier for X-ray sensitive material are displaced, along similar paths in opposite directions, about a support which is arranged between the tube and the carrier. X-ray apparatus in which such a displacement of the tube and the sensitive material is effected are used for tomographic examinations involving body-section wentgenography. Known moving devices for the displacement of the X-ray tube along dif-- ferent paths have the drawback, that for the completation of each of the displacement paths, the mechanism must be modified by replacement of one or more of the components or by locking them in a given position with respect to each other. In addition to a locking pin which is to be inserted for this purpose, use is also made of a magnetic lock.

The successive disassembly and assembly involved in the extension of conventional wentgenography with body-section wentgenography, where the X-ray tube must be displaced along different paths, give rise to a substantial loss of time which is experienced as an important drawback.

SUMMARY OF THE INVENTION The invention has for its object to provide a mechanical moving structure in which the said drawbacks are avoided. According to the invention a displaceable driving member for moving the X-ray tube is connected to one end of a tripartite arm, the other end of which is rotatable about a stationary shaft, the said arm being provided with hinged connections, the driving part thereof being connected to the adjoining part comprising a rotatable shaft, this part having a shaft which is arranged to be rotatable in the remaining part, said shafts being parallel to the stationary shaft, each sahft being individually coupled by glased transmissions to a driven shaft which is arranged to coaxial with the stationary shaft, such that, when the coaxial shafts rotate in the samedirection, the hinged parts rotate in the opposite direction, coupling members being connected to the coaxial shafts, said coupling members being actuated by a control unit so as to put these shafts into motion individually or simultaneously.

An electric motor is preferably connected to the structure, the said motor driving the moving mechanism for the driving member via control means. By using suitable transmissions, the revolution speeds of the various rotating parts of the mechanism can be adapted to a desired speed of displacement of the drivmechanism can be deactivated or by means of which another transmission ratio can be selected.

In the control unit use can be made of electromagnetic couplings which can be controlled by electrical signals and by means of which the couplings can be activated or deactivated at fixed instants according to a program.

One embodiment of a device according to the invention will be described with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a diagrammatic view of the mechanical moving structure,

FIG. 2 is a sectional view at the level of the area F in FIG. 1, and

FIG. 3 is a diagrammatic view of the arrangement of the various shafts in a plane perpendicular to the plane of the drawing of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The tripartite arm system for displacement of the driving member 1 comprises the rotatable shafts C and D which are rotatable together about the stationary shaft A. By means of the driving member an X-ray tube and a radiation receiver, each of which is provided on one end of a connecting arm, can be displaced in ing pin. The control means control the speed rotatios known manner in opposite directions along similar paths about a support for the connecting arm.

For displacement of the driving member or first body 1 an electricmotor 2 is provided. The motor 2 drives a pulley 8, provided on the worm shaft 9 of a wormgeared transmission, the worm wheel shaft of which supports a pulley 7. By means of the toothed belt 6, a flat drum 3 is driven which is arranged to be rotatable in the bearings 4 and 5, coaxial with the stationary shaft A. The belt 6 is tensioned by means of a tension roller 10. The drum 3 rotates about the stationary shaft at a speed which is dependent of the motor 2', this speed being referred to hereinafter as the reference speed V Provided in the wall of the drum 3 or third body are the bearings 12 and 13 for supporting in a rotatable manner a cylindrical box-like body '11 or second body, the shaft B or second axle of which is arranged to be accentrical with respect to the stationary shaft A or axis A, and which can rotate about this shaft together with the drum 3.

In the boxlike body 1 1 the shaft C or third axle is arranged to be eccentrical with respect to the shaft B, the

shaft C being connected to a support for the driving member 1, the shaft of which is denoted by D.

Also provided for driving the driving member 1 third and fourth shafts l4 and 15, the shaft 14 supporting two gearwheels l6 and 17. An intermediate gearwheel 19 engages thegearwheel l7 and a gearwheel 18 which is connected to the box-like body 11, so that the body 1] is moved in the same direction when the shaft 14 is rotated. The arrangement of the shaft 14 in the centre line of the drum 3 enables the body 11 to be rotated independent of the drum 3.

The hollow shaft 15 enveloping the shaft 14 supports the gearwheels 22 and 23, the gearwheel 23 being coupled to a gearwheel 24 by means of the intermediate gearwheel 25. The gearwheel 24 is connected to the centrically located shaft B in the box-like body 11, the latter shaft being connected, via gearwheels 28 and 29,

to the shaft C which is also located in the body 11. The latter shaft supports a crank arm to which the driving member 1 is connected. in this arrangement the driving member can be put into motion in' the opposite direction by rotation of the hollow shaft 15, independent of the drum 4 and the body 11.

When the motor 2 is switched on, a number of auxiliary shafts are driven which provide the transfer of movement to the various shafts of the moving mechanism. Via the pulley 8 and the shaft 9 of a worm-geared transmission with the pulley 7, the drum 3 is put into motion at a revolution speed V which is related to the revolution speed of the motor 2. i

A pulley 33 is rigidly connected to the pulley 8 on the shaft 9 and is coupled to a pulley 36 which is provided on a shaft 31. This shaft forms the worm shaft of a worm-geared transmission 42 or second transmission (FIG. 3), the worm wheel of which is coupled to a gearwheel 21 which is rigidly connected to a gearwheel 20 which engages the gearwheel 16 on the drive shaft 14.

Provided on the other end 30 of the worm shaft 9 or first transmission is a pulley 35 which cooperates with a pulley 38 on an auxiliary shaft 32. This shaft forms part of a worm-geared transmission 43 or first transmission (FIG. 3), the worm wheel of which is connected to a gearwheel 27 which forms one unit with a gearwheel 26, said gearwheel engaging the gearwheel 22 on the hollow shaft 15.

The shaft 9 also supports a freely rotatable pulley 34 which cooperates with a pulley 37 which is rigidly connected to the shaft 32.

Provided between the auxiliary shaft 31 and the pulley 36 is a second coupling member 40 which, when actuated, rigidly connects the pulley 36 to the shaft 31 and which can be freely rotated when it is switched off.

An on/off or first coupling 41 of this kind is provided on the auxiliary shaft 32 (between the shaft and the pulley 38). The freely rotatable pulley 34 is provided on the shaft 9 together with an on/off or third coupling 39.

Owing to the combination of drive possibilities of the different shafts by suitable operation of the on/off'couplings, in conjunction with the tripartite arm of the driving member 1 or first body which is'composed of the drum 3, orthird body, the second body 11, and the driving part 1 connected to the shaft C, the driving member can be displaced along numerous displacement paths. For efficient displacement of the X-ray tube in accordance with common tomography insights, the displacement isrestricted to periodic paths, the beginning and end of which coincide after completetion of a full cycle. Examples of such displacement paths are the description of a straightline, of circles of varying diameter, ellipses, and hypocycloids.

For the control of the moving device, use can be made of a control unit not shown I which offers selection facilities for adjusting the rotation angle of the different parts of the tripartite arm for the driving member 1 and the speed ratios of the various rotary movements, the selection results having the form of electrical signals which are applied to the on/off couplings, On the basis of the revolution speed V of the dru 3, the revolution speed V of the body 11 and the revolution speed V, of the driving member 1 about the shaft C can be adjusted for the periodic completion of a given path in a given relation to the revolution speed V which is characteristic of the kind of path.

For describing the straight line, settings must be chosen for the connecting shafts C and D of the tripartite arm, by rotation of the drive shafts 14 and 15, such that the shaft D is collinear with the part of the arm which is represented by the distance between the shafts A and B, the distance D-C being equal to B-C, the shaft D being adjusted at a distance from B which is equal to the distance between A and B.

When the drum 3 rotates so that the shaft B rotates about the shaft A at the revolution speed V the couplings 39, 40 and 41 are inoperative, so that the shafts 14 and 15 remain stationary. Owing to the chosen transmission ratio of the gearwheels 17-18 and 23-24 it is achieved that the driving shaft D rotates about the shaft B in the opposite direction at double the speed when the B rotates about the shaft A, so that the conditions for making the driving shaft D follow a straight line are satisfied.

The orientation of the straight line is determined by the adjustment of shaft B with respect to the stationary shaft A in the starting position when the rotation of the drum 3 commences.

For moving the driving member 1 along a circular circumference, the same adjustment can be used as in the foregoing description for the straight line; in this case the shafts 14 and 15 must be driven at the revolution speed V, of the drum 3. To this end, the couplings 40 and 41 are actuated. At the given transmission ratio between. the shafts 14-15 and the shafts B and C the revolution speeds V and V assume values at which the orientation of the driving shaft D does not change with respect to the shafts A and B.

By turning the shafts 14 and 15 with respect to each other, the orientation of the shafts C and D can be changed with respect to the shaft B, while the location of the shaft D with respect to theshaft A is changed. The radius of the circle circumference described by the driving shaft D can thus have any value between 0 and AB+BD.

For describing an ellipse, the shafts 14 is driven at the speed V, and the coupling 43 in the connection with the shaft 15 is switched off.

Any other modification of the revolution speeds of the shafts 14 and 15 with respect to each other causes the driving shaft D to describe a cycloid path. As the hypocycloid is preferably chosen for the described path, the end of the hypocycloid coinciding after each revolution with the beginning of the displacement, the speed ratiobetween the shafts 14 and 15 must be accurately determined. So as to obtain the desired displacement of the driving shaft D along a hypocycloid of this kind it was found to be effective if the revolution speed of the shaft 15 with respect to the shaft 14 satisfies the ratio 5.25/3, the shaft 14 rotating at the same speed V,

as the drum 3 about the shaft A. The couplings 39 and 40 are then actuated and coupling 41 is out of operation.

The operation of the couplings requires the utmost of any instant agreement exists between the positions of the wipers and the shafts, so that voltages derived from the wipers correspond to the rotation angles. Comparison of these voltages with present values, obtained by programming, for each of the paths for the displacement of the driving member enables the couplings to be operated at the correct instant.

What is claimed is: v

1. Apparatus for displacement of a body in predetermined paths, comprising a first body rotatable about first axle (C) mounted in a second body, the second body carrying the first body rotatable about second axle (B) mounted in a third body, the third body carrying the first and second bodies mounted in said apparatus for rotation about an axis (A), the first and second axles and axis (A) all being parallel, third and fourth axles both coaxial with axis (A) and each having driven ends, and also having driving ends coupled respectively to said first and second bodies, an electric motor with a rotary output shaft, first, second and third transmissions connectible between said motor shaft and the driven ends of said third and fourth axles, and said third body respectively, first, second and third couplings for releasably connecting said first, second and third transmissions as described, means for selectively activating said first, second and third couplings whereby said first, second and third bodies are separately and/or jointly rotatable about their respective axles.

2. Apparatus according to claim 1 wherein the distance between axis (A) and axle (B) is twice the distance between axle (B) and axle (C), and said first member rotatable about axle (C) has a crank arm whose axis is a distance from axle (C) equal to the distance between axles (B) and (C).

3. Apparatus according to claim 1 wherein said first, second and third bodies are all rotated at the same speed.

4. Apparatus according to claim 1 wherein said first, second, and third bodies, transmissions, and couplings comprise first, second and third drive systems respectively, and one of said first and second drive systems causes rotation of their corresponding first and second bodies, at a speed ratio of 5.25 3 compared to the speed of the remaining two bodies.

5. Apparatus according to claim 1 wherein said first and second bodies have speed of rotation twice that of the third and fourth coaxial axles that drive said first and second bodies.

UNITED STATES PATENT OFFICE CERT [FICA l E 01* CORRECTION Patent No, 3,808,898 Dat d y 1-974 Inventor(s) SERGE ROUGE and JACQUES LEBRA It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

a r uni IN THE HEADING:

ASSIGNEE SHOULD BE: U. S. PHILIPS CORPORATION Signed and Scaled this nineteenth Day Of Augusr1975 [SEAL] AIICSI.

RUTH C. MASON C. MARSHALL DANN AIMSHNK Officer (ummixxl'mz-cr ujlau'nrs and Trademarks ?gig? I UNITED STATES PATENT OFFICE I CERTIFICATE-OF CORRECTION Pacer at'No. 3,808,898 D d May 7, 1974 Inventor(s) SERGE ROUGE and JACQUES LEBRA Itis cer tified that erro rfiappears in the above-identified patent and that eei l keteers Patent are hereby corrected as shown below:

Col. '1, line 42, "'sahft" should be --shaft-- Col; 4, l'il 'ie 18, after; "when I the" should be inserted I -'-latte r shaftsighed-end sealed this let day of Octoberv1974.

(SEAL) Attest:

McCOY M. GIBSON JR. 4 C. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. Apparatus for displacement of a body in predetermined paths, comprising a first body rotatable about first axle (C) mounted in a second body, the second body carrying the first body rotatable about second axle (B) mounted in a third body, the third body carrying the first and second bodies mounted in said apparatus for rotation about an axis (A), the first and second axles and axis (A) all being parallel, third and fourth axles both coaxial with axis (A) and each having driven ends, and also having driving ends coupled respectively to said first and second bodies, an electric motor with a rotary output shaft, first, second and third transmissions connectible between said motor shaft and the driven ends of said third and fourth axles, and said third body respectively, first, second and third couplings for releasably connecting said first, second and third transmissions as described, means for selectively activating said first, second and third couplings whereby said first, second and third bodies are separately and/or jointly rotatable about their respective axles.
 2. Apparatus according to claiM 1 wherein the distance between axis (A) and axle (B) is twice the distance between axle (B) and axle (C), and said first member rotatable about axle (C) has a crank arm whose axis is a distance from axle (C) equal to the distance between axles (B) and (C).
 3. Apparatus according to claim 1 wherein said first, second and third bodies are all rotated at the same speed.
 4. Apparatus according to claim 1 wherein said first, second, and third bodies, transmissions, and couplings comprise first, second and third drive systems respectively, and one of said first and second drive systems causes rotation of their corresponding first and second bodies, at a speed ratio of 5.25 : 3 compared to the speed of the remaining two bodies.
 5. Apparatus according to claim 1 wherein said first and second bodies have speed of rotation twice that of the third and fourth coaxial axles that drive said first and second bodies. 